tustvold commented on code in PR #3115:
URL: https://github.com/apache/arrow-rs/pull/3115#discussion_r1023452284
##########
arrow-array/src/array/primitive_array.rs:
##########
@@ -489,6 +544,42 @@ impl<T: ArrowPrimitiveType> PrimitiveArray<T> {
)
}
}
+
+ /// Returns `PrimitiveBuilder` of this primitive array for mutating its
values if the underlying
+ /// data buffer is not shared by others.
+ pub fn into_builder(self) -> Result<PrimitiveBuilder<T>, Self> {
+ let null_buffer = self
+ .data
+ .null_buffer()
+ .cloned()
+ .and_then(|b| b.into_mutable(0).ok());
+
+ let len = self.len();
+ let null_bit_buffer = self.data.null_buffer().cloned();
+
+ let buffer = self.data.buffers()[0].clone();
Review Comment:
Same thing here, I think this needs to call `slice_with_length`
##########
arrow-buffer/src/buffer/immutable.rs:
##########
@@ -227,6 +227,25 @@ impl Buffer {
pub fn count_set_bits_offset(&self, offset: usize, len: usize) -> usize {
UnalignedBitChunk::new(self.as_slice(), offset, len).count_ones()
}
+
+ /// Returns `MutableBuffer` for mutating the buffer if this buffer is not
shared.
+ /// Returns `Err` if this is shared or its allocation is from an external
source.
+ pub fn into_mutable(self, len: usize) -> Result<MutableBuffer, Self> {
Review Comment:
Why does this take a len? How does this differ from `Buffer::length`?
##########
arrow-array/src/array/primitive_array.rs:
##########
@@ -397,6 +397,61 @@ impl<T: ArrowPrimitiveType> PrimitiveArray<T> {
unsafe { build_primitive_array(len, buffer, null_count, null_buffer) }
}
+ /// Applies an unary and infallible function to a mutable primitive array.
+ /// Mutable primitive array means that the buffer is not shared with other
arrays.
+ /// As a result, this mutates the buffer directly without allocating new
buffer.
+ ///
+ /// # Implementation
+ ///
+ /// This will apply the function for all values, including those on null
slots.
+ /// This implies that the operation must be infallible for any value of
the corresponding type
+ /// or this function may panic.
+ /// # Example
+ /// ```rust
+ /// # use arrow_array::{Int32Array, types::Int32Type};
+ /// # fn main() {
+ /// let array = Int32Array::from(vec![Some(5), Some(7), None]);
+ /// let c = array.unary_mut(|x| x * 2 + 1).unwrap();
+ /// assert_eq!(c, Int32Array::from(vec![Some(11), Some(15), None]));
+ /// # }
+ /// ```
+ pub fn unary_mut<F>(self, op: F) -> Result<PrimitiveArray<T>,
PrimitiveArray<T>>
Review Comment:
I wonder if we can use `into_builder` here, to avoid duplication?
##########
arrow-array/src/array/primitive_array.rs:
##########
@@ -1939,4 +2032,52 @@ mod tests {
array.value(4);
}
+
+ #[test]
+ fn test_into_builder() {
+ let array: Int32Array = vec![1, 2, 3].into_iter().map(Some).collect();
+
+ let boxed: ArrayRef = Arc::new(array);
+ let col: Int32Array = downcast_array(&boxed);
+ drop(boxed);
+
+ let mut builder = col.into_builder().unwrap();
+
+ builder.append_value(4);
+ builder.append_null();
+ builder.append_value(2);
+
+ let expected: Int32Array = vec![Some(4), None,
Some(2)].into_iter().collect();
Review Comment:
I would have expected `into_builder` to keep the current values?
##########
arrow-buffer/src/buffer/mutable.rs:
##########
@@ -92,6 +93,23 @@ impl MutableBuffer {
}
}
+ /// Allocates a new [MutableBuffer] from given `Bytes`.
+ pub(crate) fn from_bytes(bytes: Bytes, len: usize) -> Result<Self, Bytes> {
Review Comment:
How does the provided `len` different from `Bytes::len`?
##########
arrow-array/src/builder/buffer_builder.rs:
##########
@@ -124,6 +124,14 @@ impl<T: ArrowNativeType> BufferBuilder<T> {
}
}
+ pub fn new_from_buffer(buffer: MutableBuffer) -> Self {
+ Self {
+ buffer,
+ len: 0,
Review Comment:
```suggestion
len: buffer.len() / std::mem::size_of::<T::Native>(),
```
?
##########
arrow-array/src/builder/boolean_buffer_builder.rs:
##########
@@ -33,6 +33,10 @@ impl BooleanBufferBuilder {
Self { buffer, len: 0 }
}
+ pub fn new_from_buffer(buffer: MutableBuffer) -> Self {
Review Comment:
I think this need to be provided with the length in bits?
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